Because you’re planting indoors, the time at which your plants begin to flower is almost wholly dependent on when you want the plants to flower. Of course, you want to start flowering when the buds are at their most potent. It’s feasible to keep a marijuana plant in vegetative state for up to 10 years, but those plants certainly won’t be potent by the end of their lifespan. Before you induce flowering, you’ll probably want to know which plants are male and which ones are female. 

Determining the Sex

In general, the plants will start to “pre-flower” before you even manipulate them to flower. During this time, they will start to exhibit subtle signs as to their sex. Male plants will generally start to pre-flower earlier than females (around two weeks). This will manifest itself in the male plants growing taller than the female plants. They also might develop sacs that resemble buds but aren’t actually buds. The reason the male plants grow faster and taller than the female plants is so that they can pollinate them. The pollen in the sacs (or false buds) will drop down onto the females to start the pollination process. By contrast, the female plant will enter pre-flowering by producing a white, hairy growths at the nodes and on the top cola (the head). These are called pistils and they are what attract the male pollen to the female plant. There’s really no surefire way to determine the sex until they start exhibiting these telltale signs. You can, however, take a cutting from one of the plants, and then plant in an area separate from your garden. The cutting is basically a clone of its “mother” plant and will share the exact same genetic structure. You can then force flowering with the clone and it will definitively start to show signs of its particular sex. Then, you can go back to your garden and label each plant that you do this for.

Many growers want to determine the sex as soon as possible because the female plants will naturally produce a much better high. That’s not to say that the males are useless, but you really want to distinguish between male and female early on so that you can knowledgeably move forward. This is particularly true for growers who want “sinsemilla” buds. Sinsemilla literally means “without seed,” in Spanish, and, if the males are not allowed to pollinate the females, the plants will not produce any seeds. These seedless female plants are considerably more potent than their counterparts because they focus more attention on THC production and bud growth rather than focusing on producing seeds. In fact, you can practically see the THC resin dripping off the buds. Of course, this requires taking out the male plants early on. If you rely on your own garden to give you seeds for next year’s harvest, then this probably wouldn’t be a good idea. As mentioned before, buying seeds from a dealer or even a seed-bank is often a random grab bag. You don’t know what the seeds will become, and receiving a full batch of males is not outside the realm of possibility. Allowing your male plants to pollinate the female plants will provide you with plenty of seeds and you won’t have to pay for them. It is also possible to end up with hermaphroditic plants, which are basically just plants that have both sets of reproductive organs. Thus, they might exhibit early signs of both male and female plants. Most growers also eliminate these plants from their crop even if they want to pollinate the females. While they are self-pollinating, they will only ever produce hermaphroditic plants, and they might even pollinate some non-hermaphroditic plants. It might seem like the best of both worlds, but understand that your potency will be mostly limited when it comes to these plants. It should also be noted that male plants aren’t useless in terms of smoking either. They can still produce a little bit of a high and can also be used in culinary preparations. It’s very important to take out the male marijuana plants if you want to grow Sinsemilla. One male marijuana plant can pollinate hundreds of female’s.